1. Field of the Invention
This invention relates to an automatic accompaniment apparatus for an electronic musical instrument or a like instrument which produces predetermined chord component sounds in accordance with advancement of chords to perform automatic accompaniment.
2. Description of the Related Art
Conventionally, automatic accompaniment apparatus of the type mentioned have been realized with electronic musical instruments, for example, of the keyboard type. Some of the automatic accompaniment apparatus detect a chord from performance information inputted by operation of the keyboard and produces chord component sounds of the chord at a timing in accordance with an accompaniment pattern to perform automatic accompaniment of the chord. The accompaniment pattern can be selected from among a plurality of kinds of accompaniment patterns in accordance with the style of the tune.
By the way, a chord defines the names of sounds to be produced, and the same chord includes a plurality of inversion types in accordance with combinations of the pitches of sounds to be produced. Therefore, when the sounds are to be produced actually, the inversion type must necessarily be determined. To this end, in conventional automatic accompaniment apparatus, a particular inversion type is used fixedly to shift the sound pitches parallelly in response to a chord to produce sounds as seen from FIG. 8.
Referring to FIG. 8, in the example shown, when the chord is "C", the inversion type includes, in order from the lowest pitch, "mi" (mediant) and "so" (dominant) and "do" (tonic) and even when the chord is changed to "F", only the sound pitches are shifted, but the inversion type of the chord includes "la" (mediant), "do" (dominant) and "fa" (tonic) and is the same as that of the chord "C".
However, only a shift of the pitches with the same inversion type sometimes makes the accompaniment unnatural in that such a high jump of fourth or fifth occurs with the highest sound which is most liable to catch the ears among the accompaniment sounds, as at portions a and b in FIG. 8.